A Exotoxin ( bActerium mRNA produces and releases exotoxin A(active) B(binding)+polypeptides 释放毒素 Bacterium Receptor 与受体结合、 进入细胞 Plasma membrane 2 B(binding)com ponent of exotoxin binds to host cell Nucleus receptor and exotoxin enters cell Host cel∥ 毒素活性成分抑制细胞 功能一蛋白合成 A(active)compor ent of exotoxin 白喉毒素作用机理 alters cell function by inhibiting protein Figure 15. 4 The action of an exotoxin. A proposed model for the mechanism of action of diphtheria toxin 2021/10/18 Diphteria toxin consists of two different polypeptides: B 27 (binding) and A(active); B is required to make A active27 释放毒素 与受体结合、 进入细胞 毒素活性成分抑制细胞 功能--蛋白合成 2021/10/18 白喉毒素作用机理